U.S. patent number 4,818,813 [Application Number 07/122,507] was granted by the patent office on 1989-04-04 for complexes of technetium 99m with propylene amine oximes.
This patent grant is currently assigned to Amersham International plc.. Invention is credited to Lewis R. Canning, David P. Nowotnik.
United States Patent |
4,818,813 |
Nowotnik , et al. |
April 4, 1989 |
Complexes of Technetium 99m with propylene amine oximes
Abstract
Novel propylene amine oxime ligands have the formula ##STR1##
where each of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6,
R.sub.7 or R.sub.8 may be hydrogen, hydrocarbon, carboxyl, amine,
amide or nitrile, provided that, if R.sub.1 is the same as R.sub.9
and R.sub.2 is the same as R.sub.7, then R.sub.8 is not H. These
unsymmetrical ligands form complexes with Technetium-99m which are
capable, on injection into mammals, of crossing the blood-brain
barrier and of being retained in the brain for a time to permit
diagnosis.
Inventors: |
Nowotnik; David P. (Bucks,
GB2), Canning; Lewis R. (Bucks, GB2) |
Assignee: |
Amersham International plc.
(Bucks, GB2)
|
Family
ID: |
10568655 |
Appl.
No.: |
07/122,507 |
Filed: |
November 18, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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791995 |
Oct 23, 1985 |
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Foreign Application Priority Data
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Oct 24, 1984 [GB] |
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8426845 |
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Current U.S.
Class: |
534/14; 987/20;
564/253 |
Current CPC
Class: |
A61P
43/00 (20180101); C07F 13/005 (20130101) |
Current International
Class: |
C07F
13/00 (20060101); A61K 049/02 (); C07C 131/00 ();
C07D 295/12 (); C07F 013/00 () |
Field of
Search: |
;534/14 ;424/1.1
;564/253 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Terapane; John F.
Assistant Examiner: Caress; Virginia
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
Parent Case Text
This application is a continuation of now abandoned application
Ser. No. 791,995, filed Oct. 23, 1985.
Claims
I claim:
1. A propylene amine oxime having the general formula ##STR6##
wherein each of R.sub.1, R.sub.2, R.sub.7, R.sub.8 and R.sub.9 is
C.sub.1 to C.sub.4 alkyl, R.sub.3 and R.sub.6 are H, and R.sub.4
and R.sub.5 are H or methyl.
2. A complex of Technetium-99m with a propylene amine oxime, which
complex has the formula ##STR7## wherein each of R.sub.1, R.sub.2,
R.sub.7, R.sub.8 and R.sub.9 is C.sub.1 to C.sub.4 alkyl, R.sub.3
and R.sub.6 are H, and R.sub.4 and R.sub.5 are H or methyl.
Description
Technetium-99m (Tc-99m) is the favoured radionuclide for organ
imaging and other forms of in vivo diagnosis. Complexes of Tc-99m
have been used for investigating more parts of the body.
This invention relates to complexes of e.g. technetium-99m useful
as diagnostic pharmaceuticals, and in particular to complexes which
are capable of crossing the blood-brain barrier and being retained
in the brain for a time to permit diagnosis.
European Patent Specification No. 123504 (published on Oct. 31st,
1984) provides a lipophilic macrocyclic complex of Technetium-99m
useful as a diagnostic radiopharmaceutical which can be formed by
complexing in aqueous solution Tc-99m pertechnetate under reducing
conditions with an alkylene amine oxime containing 2 or 3 carbon
atoms in the alkylene group, which group is unsubstituted or
substituted, the complex having a core with a zero net charge,
containing an O--H--O ring closure bond, and being sufficiently
stable for parenteral administration and imaging by scintillation
scanning, any alkylene substituents present being of the kind
useful for adapting radionuclide ligands for body imaging
applications. Preferred complexes are believed to have the formula:
##STR2## where each R.sub.1, R.sub.4 and R.sub.5 is hydrogen or C1
to C12 alkyl, and each of R.sub.2 and R.sub.3 is hydrogen,
hydroxyl, C1 to C12 alkoxyl, C1 to C22 hydrocarbon which may be
alkyl, alkenyl, alkaryl, aralkyl or aryl, or tertiary amine with 1
to 20 carbon atoms, or R.sub.2 and R.sub.3 form, together with the
carbon atom to which they are attached, a cycloaliphatic ggroup
which may be amine substituted.
The present invention relates to a group of complexes, falling
within the scope of the invention of the aforesaid European patent
specification but not specifically described therein, which show
interesting properties particularly as regards brain retention.
The present invention provides a lipophilic macrocyclic complex,
useful as a diagnostic radiopharmaceutical, of Technetium-99m with
a propylene amine oxime having the general formula ##STR3## wherein
each of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6,
R.sub.7, R.sub.8 and R.sub.9 is independently hydrogen, C.sub.1
-C.sub.8 straight- or branched-chain saturated or unsaturated
alkyl, aralkyl, aryl, alkoxy, alkoxycarbonyl, alkylcarbonyl,
alkylcarbonyloxy, primary secondary or tertiary amine or amide, or
nitrile, or one or more of R.sub.1, R.sub.2 ; R.sub.3, R.sub.4 ;
R.sub.5, R.sub.6 ; R.sub.7, R.sub.8 ; R.sub.8, R.sub.9 are joined
to form a fused or spiro carbocyclic or heterocyclic ring, provided
that, when R.sub.1 is the same as R.sub.9 and R.sub.2 is the same
as R.sub.7, then R.sub.8 is not hydrogen.
The complexes are presently believed to have the general formula:
##STR4##
These complexes (and the ligands from which they derive) may have
at least one asymmetric carbon atom, namely the carbon atom to
which the group R.sup.2 is attached. Depending on the nature of
R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8, other
asymmetric carbon atoms may also be present. As a result many of
the ligands show optical isomerism. For instance Compound I (see
the Table below) exists in the form of d- and l-enantiomers.
Although we have not yet separated and investigated individual
stereoisomers, we think it quite possible that the physical and
biological properties of the Tc-99m complexes of stereoisomers may
differ from one another since such differences have shown up in
related complexes. In addition, individual stereoisomers may form
two or more technetium complexes, which may have different physical
and biological properties. This invention therefore contemplates
the propylene amine oxime ligands, and their Tc-99m complexes, both
as isomeric mixtures and in the form of one or more of their
separated geometrical and stereoisomers.
Each of the aforementioned propylene amine oxime stereoisomers can
itself exist in four different isomeric forms by virtue of the
restricted rotation about their CN bonds of the two oxime groups.
The isomers may have different physical properties (m.pt., b.pt.)
and can be separated by chromatographic techniques (TLC and HPLC).
Their interconversion is generally facile and is catalysed by
mineral or Lewis acids or metal ions. The thermodynamically
preferred isomer is expected to be that which provides maximum
separation of the bulkier groups. It is probable that the four
isomers (of each stereoisomer) may form Tc-99m complexes having
different biodistribution properties. The invention therefore
contemplates the propylene amine oxime ligands, and their Tc-99m
complexes, both in the form of mixtures of the isomers and of
individual isomers.
The complexation reaction between the propylene amine oxime ligand
and pertechnetate (TcO.sub.4.sup.- from a Mo-99/Tc-99m generator)
may be carried out in aqueous or aqueous/organic solution under
reducing conditions. Stannous salts are convenient reducing agents,
but other reducing agents are well known for this type of reaction
and can be used. Since the complexes of this invention contain
Tc-99m bound rather strongly, they can alternatively be prepared by
a process of ligand exchange. The preparation of Tc-99m complexes
by reducing pertechnetate in the presence of a complexing ligand is
well-known; the conditions for such general reactions are also
well-known and can be used in the particular instance of this
invention.
The propylene amine oximes are unsymmetrical about the carbon atom
to which groups R.sub.4 and R.sub.5 are attached and are believed
to be in general new compounds. They may be prepared by the general
route outlined in the following reaction scheme: ##STR5##
Specific examples of propylene amine oximes that can be used as
ligands to make complexes according to this invention are the
following:
______________________________________ No. R.sub.1 R.sub.2 R.sub.3
R.sub.4 R.sub.5 R.sub.6 R.sub.7 R.sub.8 R.sub.9
______________________________________ 1 CH.sub.3 CH.sub.3 H H H H
CH.sub.3 CH.sub.3 CH.sub.3 2 C.sub.2 H.sub.5 CH.sub.3 H H H H
CH.sub.3 CH.sub.3 CH.sub.3 3 CH.sub.3 CH.sub.3 H CH.sub.3 CH.sub.3
H CH.sub.3 CH.sub.3 CH.sub.3 4 CH.sub.3 C.sub.2 H.sub.5 H CH.sub.3
CH.sub.3 H CH.sub.3 CH.sub.3 CH.sub.3 5 CH.sub.3 CH.sub.3 H H H H
CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 6 CH.sub.3 C.sub.2 H.sub.5 H H H
H CH.sub.3 CH.sub.3 CH.sub.3 7 C.sub.2 H.sub.5 CH.sub.3 H H H H
CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 8 CH.sub.3 CH.sub.3 H H H H
C.sub.2 H.sub.5 C.sub.2 H.sub.5 CH.sub.3 9 i-3.sub.3 H.sub.7
CH.sub.3 H H H H CH.sub.3 CH.sub.3 CH.sub.3
______________________________________
There follows an example of the preparation of a complex according
to the invention of technetium-99m with a ligand No. 2 of the above
Table.
EXAMPLE 1
1. Preparation of 4,8-diaza-3,3,9-trimethyl-dodecane-2,10-dione
bisoxime
(i) 3-chloro-3-methyl-2-nitrosobutane (I)
A mixture of 2-methylbut-2-ene (18.5 cm.sup.3) and isoamyl nitrite
(19.5 cm.sup.3) was cooled to -10.degree. C. Concentrated
hydrochloric acid (17.5 cm.sup.3) was added at a rate so as to
maintain the temperature below 0.degree. C. Stirring was continued
for 1/2 hour after the addition was complete. The precipitate was
filtered, washed well with cold (-20.degree. C.) ethanol (4.times.5
cm.sup.3) and dried in vacuo giving the product as a white solid
(8.6 g).
(ii) N-(3-Aminopropyl)-1-amino-1,1-dimethyl-2-butanone oxime
(II)
A solution of 3-chloro-3-methyl-2-nitrosobutane (25.5 g) in
methanol (180 cm.sup.3) was added dropwise to a stirred solution of
1,3-diaminopropane (47 cm.sup.3) in methanol (75 cm.sup.3) at
0.degree. C. After the addition was complete the mixture was
refluxed for 6 hours. Removal of the methanol in vacuo gave a
yellow oil which was slurried in water (50 cm.sup.3). The white
precipitate was removed by filtration and the pH of the aqueous
solution adjusted to about 11. After saturating with salt the
solution was continuously extracted with dichloromethane for 36
hours. The organic phase was dried (MgSO.sub.4) and concentrated in
vacuo giving a yellow oil. Recrystallisation from ether/petrol gave
pure product as a white crystalline solid, 9.9 g. Mpt.
69.degree.-72.degree. C.
NMR (.sup.1 H, 200 MHz, d.sub.6 -DMSO): 2.58(2H, t, CH.sub.2 N),
2.24(2H, t, CH.sub.2 N), 1.70(3H, s, CMe), 1.42(2H, q, CH.sub.2),
1.11(6H, s, CMe.sub.2)ppm.
(iii) Preparation 2,3-pentanedione-3-oxime (III)
Methyl nitrite was bubbled, at a rate sufficient to maintain
vigorous reflux, into a well stirred mixture of 2-pentanone (102
g), ether (400 cm.sup.3) and concentrated hydrochloric acid (15
cm.sup.3). The methyl nitrite gas was generated by the dropwise
addition of a solution of concentrated sulphuric acid (100
cm.sup.3) and water (95 cm.sup.3) onto a stirred slurry of sodium
nitrite (112 g), methanol (66 g) and water (75 cm.sup.3). After the
addition was complete the mixture was neutralised with saturated
aqueous sodium bicarbonate (32 g in 300 cm.sup.3). The ether layer
was separated and the aqueous layer extracted with more ether. The
combined organic layers were dried and concentrated in vacuo giving
a yellow oil which crystallised on standing. Recrystallisation from
hot hexane gave pure product (67 g), mp 54.degree.-5.degree. C.
(iv) 4,8-Diaza-3,3,9,-trimethyl-dodeca-8-ene-2,10-dione bisoxime
(IV)
2,3-Pentanedione-3-oxime (2.0 g) was dissolved in ethanol (4
cm.sup.3) at 70.degree. C.
1,3-Diaminopropane-N-(2-methyl-3-butanone)oxime (3.05 g) was added
in portions with stirring. Stirring was continued for 15 minutes
and then the ethanol was removed in vacuo. Recrystallisation of the
residue from dichloromethane/petrol gave the product as a white
solid (3.7 g), mp 115.degree.-116.degree. C.
NMR(.sup.1 H, 200 MHz, d.sub.6 -DMSO): 11.30, 10.31 (each 1H, s,
OH), 3.39 (2H, t, CH.sub.2 N), 2.50(2H, q, N.dbd.CCH.sub.2),
2.32(2H, t, CH.sub.2 NH), 1.96(3H, s, N.dbd.CCH.sub.3 imine), 1.69
(5H, s+m, N.dbd.CCH.sub.3 +CH.sub.2 CH), 1.11 (6H, s, CMe.sub.2),
0.91 (3H, t, CH.sub.2 CH.sub.3) ppm.
(v) 4,8-Diaza-3,3,9-trimethyl-dodecane-2,10-dione bisoxime (V)
4,8-Diaza-3,3,9-trimethyl-dodeca-8-ene-2,10-dione bisoxime (3.5 g)
was stirred in 95% aqueous ethanol (33 cm.sup.3) at 0.degree. C.
Sodium borohydride (0.10 g) was added in portions to the stirred
mixture over 1/2 hour. Stirring was continued for 2 hours at
0.degree. C. and then water (12 cm.sup.3) was added. The mixture
was stirred well for 2 hours and then the ethanol was removed in
vacuo. Water (8 cm.sup.3) was added and the pH adjusted to about
11. After saturating with NaCl the aqueous phase was extracted with
dichloromethane (5.times.40 cm.sup.3). The combined organic layers
were dried (MgSO.sub.4) and concentrated in vacuo giving a viscous
yellow oil (3.1 g). Recrystallisation from dichloromethane/ether
and then dichloromethane/petrol gave pure product (0.78 g), mp
94.degree.-6.degree. C.
2. Preparation of Tc-99m complex of ligand (V)
The following general method was used to prepare Tc-99m complexes.
The first step involves the preparation of a solution of the ligand
within a pH range of 7.5 to 8.5. Both the physical form and the
nature of the ligand will influence the preferred method for the
preparation of the solution.
(i) The ligand as a water soluble salt (for example, the mono, di,
or trihydrochloride salt). 2 to 3 mg of the ligand is dissolved in
0.5 ml of saline, and the pH of the solution adjusted to be within
the desired range by the addition of 0.5 ml of 0.02M sodium
bicarbonate solution in saline.
(ii) A water soluble free base. Approximately 2 mg of the ligand is
dissolved in 0.5 ml of 10.sup.-3 M HCl, and the pH of the solution
adjusted to 7.5 to 8.5 by the addition of 0.5 ml 0.02M sodium
bicarbonate solution in saline.
(iii) A free base or salt of the ligand with poor water solubility
2 to 3 mg of the ligand is dissolved in 0.5 ml of ethanol and 0.5
ml of 0.02M sodium bicarbonate solution in saline is added to
adjust the pH to the required level.
To the solution of the ligand at the required pH is added 0.2 ml of
a saturated solution of stannous tartrate in saline and 0.5 to 1.5
ml of Tc-99m pertechnetate, obtained from a Mo-99/Tc-99m generator
system. Analysis of the resultant mixture indicated that reduction
of pertechnetate (to a lower oxidation form of technetium), and
complexation of the reduced technetium to the ligand is complete
after standing at ambient temperature for 10 minutes.
EXAMPLES 2-7
Ligands 1 and 3-7 were prepared by methods corresponding to Example
1. The following melting points were recorded.
______________________________________ Compound m.pt. .degree.C.
______________________________________ 1 124-6 2 94-6 3 100-102 4
108-111 5 111-112 6 51-3 7 112-114 8 94-5 9 101-2
______________________________________
NMR spectra were recorded in d.sub.6 -DMSO at 200 MHz. The chemical
shifts (.delta., ppm), with the integration and multiplicity in
parenthesis, are given in Table I:
TABLE 1
__________________________________________________________________________
COM- POUND OH R.sub.9 R.sub.7,8 R.sub.4,5 R.sub.2 R.sub.1 CH.sub.2
N C .sub.--HR.sub.2
__________________________________________________________________________
1 10.48(1H,brs) 1.70(3H,s) 1.13(6H,s) 1.48(2H,m) 1.07(3H,d)
1.66(3H,s) 2.41(2H,t) 3.25(1H,q) 10.37(1H,brs) 2.32(2H,t) 2
10.35(1H,s) 1.69(3H,s) 1.10(6H,s) 1.42(2H,m) 1.05(3H,m) CH.sub.2
2.20(2H,m) 2.20(2H,m) 3.22(1H,q) 10.22(1H,s) CH.sub.3 1.05(3H,m)
2.37(2H,t) 3 10.34(1H,s) 1.70(3H,s) 1.17(6H,s) 0.78(6H,s)
1.07(3H,d) 1.65(3H,s) 2.1-2.0 3.12(1H,q) 10.27(1H,s) (4H,m) 4
10.32(2H,brs) 1.69(3H,s) 1.11(6H,s) 0.78(6H,s) CH.sub.2 1.45(2H,m)
1.62(3H,s) 2.15-1.95 2.84(1H,brm) CH.sub.3 0.78(3H,m) (4H,brm) 5
10.28(2H,brs) CH.sub.2 2.35-2.25 1.12(6H,s) 1.41(2H,m) 1.03(3H,m)
1.64(3H,s) 2.35-2.25 3.16(1H,q) (2H,m) (4H,m) CH.sub.3 1.02(3H,m) 6
10.36(1H,s) 1.69(3H,s) 1.10(6H,s) 1.42(2H,m) CH.sub.2 1.42(2H,m)
1.62(3H,s) 2.20(2H,t) 2.90(1H,t) 10.31(1H,s) CH.sub.3 0.76(3H,t)
2.33(2H,m) 7 10.25(1H,brs) CH.sub.2 2.20(2H,m) 1.12(6H,s)
1.42(2H,m) 1.03(3H,d) CH.sub.2 2.20(2H,m) 2.36(2H,t) 3.17(1H,q)
10.19(1H,brs) CH.sub.3 1.01(3H,m) CH.sub.3 1.01(3H,m) 2.20(2H,m) 8
10.39(1H,s) 1.67(3H,s) CH.sub.2 1.43(4H,m) 1.43(2H,m) 1.05(3H,d)
1.64(3H,s) 2.36(2H,t) 3.17(1H,q) 10.25(1H,s) CH.sub.3 0.64(6H,t) 9
10.32(1H,s) 1.69(3H,s) 1.10(6H,s) 1.43(2H,m) 1.08(3H,d) CH.sub.3
1.13(6H,d) 2.24(2H,t) 3.18(1H,q) 10.16(1H,s) CH 2.82(1H,m)
2.23(2H,t)
__________________________________________________________________________
Abbreviations: s = singlet d = doublet t = triplet q = quartet m =
multiplet br = broad
Complexes were prepared by the method described in Example 1.
EXAMPLE 8
In Vivo biodistribution studies
0.1 ml of the Tc-99m complex solution is administered by
intravenous injection (lateral tail vein) to each of 5 rats
(140-220 g). The injected dose is equivalent to approximately 200
Ci of Tc-99m. Three rats are sacrificed at 2 minutes post
injection, and the two rats one to two hours post injection. At
dissection the organs and tissue samples shown in the following
Table are taken, and assayed for radioactivity. The uptake in each
organ or tissue is calculated as a percentage of total activity
recovered. Results reported in Table II.
BIODISTRIBUTION DATA
TABLE II ______________________________________ % id/organ Compound
Sacrifice Brain Blood Muscle Lung Liver
______________________________________ 2 minute sacrifice 1 1.56
8.49 51.99 2.55 19.14 2 1.24 7.57 36.50 2.45 18.06 3 1.03 7.17
30.15 1.17 21.56 4 1.0 4.08 23.9 1.25 11.75 5 0.62 5.38 16.77 2.18
25.27 6 1.1 5.69 26.62 2.31 24.86 7 1.15 7.11 30.90 3.67 20.10 8
1.10 6.26 38.27 2.46 18.36 9 0.82 5.50 30.53 1.99 20.85 1-2 hour
sacrifice 1 2 hour 1.42 4.32 10.81 1.81 22.07 2 2 hour 0.90 3.62
15.1 1.49 12.07 3 2 hour 0.57 3.50 13.95 0.66 16.76 4 1 hour 0.29
3.26 9.05 0.64 23.34 5 1 hour 0.53 2.38 7.53 0.64 18.77 6 1 hour
0.66 2.69 6.37 1.07 17.08 7 1 hour 1.06 4.07 11.30 1.66 16.57 8 1
hour 0.64 3.16 11.25 2.03 15.89 9 1 hour 0.19 3.85 6.15 0.88 24.12
______________________________________
The brain retention of these complexes is in general surprisingly
superior to that of the complexes described in EP A No. 123504.
* * * * *